add a copy/paste chat sample and some re-shuffling of the other apps

Summary:

* replace `chat2` with a clone of Matt's copy/paste sample from `uproxy-networking`
* `freedomchat-chromeapp` really didn't need to be a Chrome app -- make it a web page
* rename `freedomchat-webpage` -> `freedom-chat-webpage`
Yes! Now, in `freedom-module.ts` this "rhymes" with `dataFromPeer` (I had named it to make sense with `signalForPeer` in `main.ts` -- oops).